The present invention relates to Magnetic Resonance Imaging control systems, and more particularly, to an in-room MRI display terminal and remote control system which enables control of the MRI scanner and the images displayed from within the MRI exam room.
Magnetic Resonance Imaging ("MRI") is a well-known procedure for obtaining detailed, two- and three-dimensional images of a patient based upon nuclear magnetic resonance ("NMR") principles. MRI is well suited for the imaging of soft tissues, and has been used primarily for diagnosing internal injuries or other medical ailments. A typical MRI system will generally include a magnet capable of producing a very strong homogenous magnetic field, sized to cover or surround a portion of a patient's anatomy; a radio frequency ("RF") transmitter and receiver system, including a receiver coil which surrounds the portion of the patient's anatomy under study; a magnetic gradient system to localize in space a particular portion of the patient's anatomy under study; and a computer processing/imaging system for receiving the signals from the receiver coil and for processing the signals into interpretable data, such as visual images for viewing by the physician or MRI attendant. Additional information regarding MRI technology and equipment can be found in Van Nostrand's Scientific Encyclopedia, Eighth Edition, pp. 2198-2201 and U.S. Department of Heath and Human Services, "A Primer on Medical Device Interactions with Magnetic Resonance Imaging Systems," Feb. 7, 1997. The general principles and associated equipment used in MRI is well-known, and as such, additional disclosure is not necessary.
Conventionally, an MRI system will include two rooms: an RF shielded room (Faraday cage) primarily occupied by the MRI magnet and patient table (the "exam room"), and a control room where the other equipment is typically located and where the MRI technologist typically controls the MRI process. The magnet and patient table are located in the shielded exam room. Other equipment is located outside the shielded exam room because, due to the nature of MRI, any device or object transmitting or leaking RF signals can potentially negatively interfere with the imaging process.
The advent of "open" MRI systems provided patients with a more comfortable examination process and also provided the MRI attendants and physicians access to the patient while a portion of that patient is being viewed or scanned by the MRI system. An example of such an open MRI system is the AIRIS.RTM. II system, commercially available from Hitachi Medical Systems America, Inc. Open MRI systems enable physicians and other MRI attendants to perform interventional surgery or other therapeutic procedures on the patient while the MRI system is scanning and producing images.
Open MRI systems also facilitate "MR fluoroscopy" which combines near real-time signal acquisition, image reconstitution and image display with such interventional procedures. Accordingly, when utilizing MR fluoroscopy the physician monitors, substantially in real-time (approximately one image per second), a two- or three-dimensional image of the anatomy while performing a medical procedure on that anatomy. For example, if the physician wishes to insert an MR compatible tool, such as a needle or endoscope for example, into a particular organ, while missing other organs, the physician monitors the path of the needle or tool, internally, by viewing the MRI image on a viewing screen. During the MR fluoroscopy procedure, therefore, it is desirable (if not imperative) that a display/control terminal be positioned in close proximity to the physician performing the fluoroscopy procedure; and additionally, it would also be beneficial that this physician be able to easily control the MRI system during the fluoroscopy procedure.
In other intra-operative uses of the MRI machine not necessarily involving the use of MR fluoroscopy, it is often desirable for the image review of just-sequenced patients images to be done inside the MRI exam room since the physician may be unable to leave the MRI exam room due to the desire to maintain as sterile an environment as possible. This problem can arise even in MRI systems in which the scanner is not as "open" as in the AIRIS.RTM. II system mentioned above.
A disadvantage with MRI systems is that, due to the high magnetic fields and the susceptibility to RF interference inherent in the MRI process, it is very difficult to locate control/display terminals within the exam room. Video signals transmitted by the remote signal processing systems into the exam room over conductive cables will tend to leak RF interference into the exam room due to the RF frequencies of the video signals. Additionally, in the past the control of the functions and operation of the MRI scanner and displays from within the exam room is limited to function-specific switches (button) and, in the case of graphical user interfaces for in-room control terminals, tethered cursor-control devices (mouse, trackball, joy-stick, etc.) and/or keyboards. Such cursor-control devices require horizontal surface space, which is at a premium in an interventional setting, and tethered devices may severely restrict the physician's location within the exam room.
Accordingly, it would advantageous to allow the physicians or attendants within the exam room to easily view the MRI images and to directly control the MRI system during the fluoroscopy process. It would also be advantageous to provide an MRI system in which images from a number of sources can be displayed selectively under control of the physician or attendant within the exam room. An MRI compatible control system for controlling any piece of equipment from within the MRI exam room would also be advantageous for the medical industry and field.